Todd,
I guess a problem with discussing this is actually trying to picture a situation we'd find ourselves in where, in an urban environment, we'd actually have to forage for food to survive off of.
?
A very, very bad situation if all you have is foraging for plants. Maybe the kind we try to prepare for here?
And, of course, in almost any lesser emergency situation wouldn't it be nice to stretch your supplies and add something nutritious and tasty?